fa Bioactive Compounds پژوهشي Research Medicinal plants are useful in perfumery, pharmaceutical, and food industries. Recognition of compounds and functional groups of these plants helps to more understand their structure, medicinal and therapeutic applications. Essential oils and extracts are used to recognition structure. One of these spectroscopic methods for identifying functional groups in medicinal plants is Fourier-transform infrared spectroscopy (FTIR) spectroscopy. This study aimed to identify the functional groups of medicinal plants of <em>Oliveria decumbent</em> native to Ilam by the FTIR method. Based on the results obtained, it was determined that this plant includes 15 spectra including groups O-H, C-H, C = O, C = C, N-O, C-O, C-N, and C-I. So, the present study concluded that the <em>Oliveria decumbens</em> possessed strong functional groups. Medicinal plant, Oliveria decumbens, FTIR 48 53 http://pbp.medilam.ac.ir/browse.php?a_code=A-10-29-2&slc_lang=fa&sid=1 Amir Soltanbeigi amir.soltanbeigi@afsu.edu.tr 10031947532846001162 10031947532846001162 No Faculty of Pharmacy, Basic Pharmaceutical Sciences Dep., Medicinal & Aromatic Plants, Culture & Technology, Turkey Samira Shokri shokrisamira22@yahoo.com 10031947532846001163 10031947532846001163 No Department of Environmental Health Engineering, Division of Food Safety & Hygiene, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Saber Abbaszadeh saberabaszade1370@gmail.com 10031947532846001164 10031947532846001164 Yes Department of Biochemistry and Genetics, School of Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran